Support tape shield cables

[AnjoMan]

Carsons supports overhead wires as well as underground cables where each phase conductor has a concentric neutral. However, there is another somewhat common cable typology, the tape-shield. This is where the cable has a thin conductive shield around the insulation, and then there is a separate neutral cable pulled underground alongside the phase conductors.

Since we already support Concentric Neutrals using the modified carsons equations, it shouldn't be too hard to build a TapeShieldCarsonsEquations that implements the particular geometric equivalents for a tape shield cable.

Part of the work would involve exploring IEEE, OpenDSS or other resources for sample calculations that can be used as tests for this calculation. IEEE4/13 has a AN example, but we'd want to also have example calculations for 2- and 3-phase cables.